4月29日 类的方法

using System;
using System.Collections.Generic;

namespace BankAccountDemo
{
    // 银行账户类
    public class BankAccount
    {
        // ========== 字段 ==========
        private string accountNumber;      // 账户号
        private string holderName;         // 持有人姓名
        private decimal balance;           // 余额
        private DateTime createDate;       // 创建日期
        private List<string> transactions; // 交易记录

        // ========== 构造方法 ==========
        public BankAccount(string accountNumber, string holderName)
        {
            this.accountNumber = accountNumber;
            this.holderName = holderName;
            this.balance = 0;
            this.createDate = DateTime.Now;
            this.transactions = new List<string>();
            
            // 记录开户交易
            RecordTransaction($"开户，初始余额: ¥0.00");
        }

        // ========== 方法 ==========
        
        // 存款
        public void Deposit(decimal amount)
        {
            if (amount <= 0)
            {
                Console.WriteLine("存款金额必须大于0！");
                return;
            }
            
            balance += amount;
            RecordTransaction($"存款: +¥{amount:F2}，余额: ¥{balance:F2}");
            Console.WriteLine($"存款成功！存入 ¥{amount:F2}");
        }

        // 取款
        public bool Withdraw(decimal amount)
        {
            if (amount <= 0)
            {
                Console.WriteLine("取款金额必须大于0！");
                return false;
            }
            
            if (amount > balance)
            {
                Console.WriteLine($"余额不足！当前余额: ¥{balance:F2}，需要: ¥{amount:F2}");
                return false;
            }
            
            balance -= amount;
            RecordTransaction($"取款: -¥{amount:F2}，余额: ¥{balance:F2}");
            Console.WriteLine($"取款成功！取出 ¥{amount:F2}");
            return true;
        }

        // 查询余额
        public decimal GetBalance()
        {
            return balance;
        }

        // 打印账户信息
        public void PrintInfo()
        {
            Console.WriteLine("\n========== 账户信息 ==========");
            Console.WriteLine($"账户号: {accountNumber}");
            Console.WriteLine($"持有人: {holderName}");
            Console.WriteLine($"当前余额: ¥{balance:F2}");
            Console.WriteLine($"开户日期: {createDate:yyyy-MM-dd HH:mm}");
            Console.WriteLine("==============================\n");
        }

        // 打印交易记录
        public void PrintTransactions()
        {
            Console.WriteLine("\n========== 交易记录 ==========");
            if (transactions.Count == 0)
            {
                Console.WriteLine("暂无交易记录");
            }
            else
            {
                foreach (var transaction in transactions)
                {
                    Console.WriteLine(transaction);
                }
            }
            Console.WriteLine("==============================\n");
        }

        // 计算利息（年利率3%，计算本月利息）
        public void CalculateInterest()
        {
            decimal monthlyRate = 0.03m / 12; // 月利率
            decimal interest = balance * monthlyRate;
            balance += interest;
            RecordTransaction($"利息结算: +¥{interest:F2}，余额: ¥{balance:F2}");
            Console.WriteLine($"利息已结算！获得利息: ¥{interest:F2}");
        }

        // 私有方法：记录交易
        private void RecordTransaction(string description)
        {
            string record = $"[{DateTime.Now:yyyy-MM-dd HH:mm:ss}] {description}";
            transactions.Add(record);
        }
    }

    // 程序入口
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("=== 欢迎使用简易银行账户系统 ===\n");
            
            // 创建账户
            Console.Write("请输入账户号: ");
            string accNum = Console.ReadLine();
            Console.Write("请输入持有人姓名: ");
            string name = Console.ReadLine();
            
            BankAccount myAccount = new BankAccount(accNum, name);
            Console.WriteLine("\n账户创建成功！\n");

            // 主菜单循环
            bool running = true;
            while (running)
            {
                Console.WriteLine("请选择操作：");
                Console.WriteLine("1. 存款");
                Console.WriteLine("2. 取款");
                Console.WriteLine("3. 查询余额");
                Console.WriteLine("4. 查看账户信息");
                Console.WriteLine("5. 查看交易记录");
                Console.WriteLine("6. 结算利息");
                Console.WriteLine("0. 退出");
                Console.Write("\n> ");
                
                string choice = Console.ReadLine();
                Console.WriteLine();

                switch (choice)
                {
                    case "1":
                        Console.Write("请输入存款金额: ");
                        if (decimal.TryParse(Console.ReadLine(), out decimal depositAmount))
                        {
                            myAccount.Deposit(depositAmount);
                        }
                        else
                        {
                            Console.WriteLine("输入无效！");
                        }
                        break;

                    case "2":
                        Console.Write("请输入取款金额: ");
                        if (decimal.TryParse(Console.ReadLine(), out decimal withdrawAmount))
                        {
                            myAccount.Withdraw(withdrawAmount);
                        }
                        else
                        {
                            Console.WriteLine("输入无效！");
                        }
                        break;

                    case "3":
                        Console.WriteLine($"当前余额: ¥{myAccount.GetBalance():F2}\n");
                        break;

                    case "4":
                        myAccount.PrintInfo();
                        break;

                    case "5":
                        myAccount.PrintTransactions();
                        break;

                    case "6":
                        myAccount.CalculateInterest();
                        break;

                    case "0":
                        running = false;
                        Console.WriteLine("感谢使用，再见！");
                        break;

                    default:
                        Console.WriteLine("无效选项，请重新选择。\n");
                        break;
                }
                
                if (running)
                {
                    Console.WriteLine("按任意键继续...");
                    Console.ReadKey();
                    Console.Clear();
                }
            }
        }
    }
}